Experimental and Numerical Investigations of the Solidity Effect on a Linear Compressor Cascade

Abstract

The solidity in a compressor is defined as the ratio of the aerodynamic chord over the peripheral distance between two adjacent blades, the pitch. The choice of this parameter represents a crucial step in the whole design process. Most of the studies addressing this issue are based on low-speed compressor cascade correlations. In that prospect, aiming at updating those correlation data as well as improving the physical understanding of the solidity effect on compressor performance, both experimental and numerical high-speed cascade investigations have been carried out at the von Karman Institute. The profile is a state-of-the-art controlled diffusion blade, representative of a low pressure compressor stator mid-span profile. The performance in terms of total pressure losses and deviation have been measured in the high-speed C3 cascade facility for three different solidities at six incidences and two Mach numbers. Based on the experimental results, a numerical linear cascade model has been built and computations have been run with FINE/Turbo at the same conditions as the measurements. The quality of the numerical predictions is discussed over the whole incidence range and, in particular, big discrepancies are highlighted at off-design incidences. Focusing on the solidity effects at mid-span, both experimental and numerical results are compared with existing correlations. The establishment of updated correlations for such controlled diffusion profile is addressed for both deviation and total pressure losses and at both optimum and off-design conditions.